My office was a trailer: Start-ups that started from nothing

More From Shark Tank

Start-ups that started up from nothing

Successful businesses look calm from the outside.

Behind the scenes, it's often a different story. Their creation can be protracted and plagued with turmoil, and involving irregular meals, office spaces in bad neighborhoods and a pervasive fear that it could all fall apart at any moment.

CNBC.com spoke with entrepreneurs who lived this reality and started businesses from threadbare beginnings. Today you would never know how much they struggled to bring their companies to life, but as they'll tell you themselves, it was a lot harder than it looks.

Read ahead to find out just how hard it was.

—By CNBC's Daniel BukszpanPosted 4 Feb. 2014

Tuesday nights have more bite with back-to-back episodes of "Shark Tank" on CNBC.